Trading has been extremely volatile for the last few months, but if Tuesday’s early gain endures, it will be the third in a row for the S&P 500. The index hasn’t had a three-day winning streak since late November.

TRADE TALKS: There was no evidence Tuesday morning that the U.S. and China made significant progress in their latest round of trade talks, and experts say it will take months for them to resolve the causes over the trade war, which include disagreements over Beijing’s handling of technology and intellectual property. But after the market’s plunges in October and December, investors have become notably more optimistic about an eventual deal. An agreement between the two biggest economic powers in the world could remove a major obstacle to global economic growth.

ALL THE LIVE-LONG DAY: Union Pacific surged 9.6 percent to $152 after it hired longtime Canadian National railroad executive Jim Vena as its chief operating officer. Vena will oversee the company’s effort to implement a new scheduling program based on what other railroads including Canadian National have been doing for years.

Other transportation and industrial companies also jumped Tuesday as investors became more optimistic about continued economic growth. Rival railroad Norfolk Southern gained 3.1 percent to $156.298 while aerospace giant Boeing rose 2.1 percent to $334.89 and construction equipment company Caterpillar climbed 2.4 percent to $131.29.

ENERGY: Like stocks, oil prices continued their recent rally. U.S. crude was on track to rise for the eight day in the last nine as it jumped 2 percent to $49.48 per barrel in New York. Brent crude, used to price international oils, was up 1.7 percent to $58.32 a barrel in London.

U.S. crude dropped from about $76 a barrel in early October to a low of $42 a barrel on Dec. 24 as investors worried about slowing economic growth and a supply glut. The modest recovery in oil prices has sent energy companies higher, and the S&P 500 index of energy companies has risen 7 percent so far in 2019.

LEADERS: Among technology companies, Apple rose 1.2 percent to $149.65 and Microsoft gained 0.9 percent to $102.99 while IBM added 1.8 percent to $120.23. Among consumer-focused companies, Amazon rose 1.8 percent to $1,660. Amazon surpassed Microsoft to become the most valuable publicly-traded company on Monday and built on that lead Tuesday. Elsewhere Nike picked up 1.2 percent to $76.66.

POWER DOWN: California utility PG&E slumped another 10 percent to $17.05 after S&P Global Ratings slashed the company’s credit rating to non-investment grade or “junk” status. The stock had plunged 22 percent Monday on reports PG&E was considering filing for bankruptcy, as it faces huge potential legal liabilities related to deadly wildfires in 2017 and 2018.